[bindings] Implement an ExperimentEnabled IDL extended attribute.

third_party/WebKit/Source/bindings/scripts/v8_attributes.py

 # Copyright (C) 2013 Google Inc. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 # copyright notice, this list of conditions and the following disclaimer
@@ skipping 81 matching lines @@
     cached_attribute_validation_method = extended_attributes.get('CachedAttribute')
     keep_alive_for_gc = is_keep_alive_for_gc(interface, attribute)
     if cached_attribute_validation_method or keep_alive_for_gc:
         includes.add('bindings/core/v8/V8HiddenValue.h')
 
     context = {
         'access_control_list': access_control_list(interface, attribute),
         'activity_logging_world_list_for_getter': v8_utilities.activity_logging_world_list(attribute, 'Getter'),  # [ActivityLogging]
         'activity_logging_world_list_for_setter': v8_utilities.activity_logging_world_list(attribute, 'Setter'),  # [ActivityLogging]
         'activity_logging_world_check': v8_utilities.activity_logging_world_check(attribute),  # [ActivityLogging]
+        'api_experiment_name': v8_utilities.api_experiment_name(attribute),  # [APIExperimentEnabled]
         'argument_cpp_type': idl_type.cpp_type_args(used_as_rvalue_type=True),
         'cached_attribute_validation_method': cached_attribute_validation_method,
         'conditional_string': v8_utilities.conditional_string(attribute),
         'constructor_type': constructor_type,
         'cpp_name': cpp_name(attribute),
         'cpp_type': idl_type.cpp_type,
         'cpp_type_initializer': idl_type.cpp_type_initializer,
         'deprecate_as': v8_utilities.deprecate_as(attribute),  # [DeprecateAs]
         'enum_type': idl_type.enum_type,
         'enum_values': idl_type.enum_values,
@@ skipping 35 matching lines @@
         'name': attribute.name,
         'only_exposed_to_private_script': is_only_exposed_to_private_script,
         'private_script_v8_value_to_local_cpp_value': idl_type.v8_value_to_local_cpp_value(
             extended_attributes, 'v8Value', 'cppValue', bailout_return_value='false', isolate='scriptState->isolate()'),
         'property_attributes': property_attributes(interface, attribute),
         'reflect_empty': extended_attributes.get('ReflectEmpty'),
         'reflect_invalid': extended_attributes.get('ReflectInvalid', ''),
         'reflect_missing': extended_attributes.get('ReflectMissing'),
         'reflect_only': extended_attribute_value_as_list(attribute, 'ReflectOnly'),
         'runtime_enabled_function': v8_utilities.runtime_enabled_function_name(attribute),  # [RuntimeEnabled]
+        'runtime_enabled_function_only': v8_utilities.runtime_enabled_conditional(attribute.extended_attributes),
         'should_be_exposed_to_script': not (is_implemented_in_private_script and is_only_exposed_to_private_script),
         'world_suffixes': ['', 'ForMainWorld']
                           if 'PerWorldBindings' in extended_attributes
                           else [''],  # [PerWorldBindings]
     }
 
     if is_constructor_attribute(attribute):
         update_constructor_attribute_context(interface, attribute, context)
     if not has_custom_getter(attribute):
         getter_context(interface, attribute, context)
@@ skipping 337 matching lines @@
     return attribute.idl_type.name.endswith('Constructor')
 
 
 def update_constructor_attribute_context(interface, attribute, context):
     context['needs_constructor_getter_callback'] = context['measure_as'] or context['deprecate_as']
     # When the attribute name is the same as the interface name, do not generate
     # callback functions for each attribute and use
     # {{cpp_class}}ConstructorAttributeSetterCallback.  Otherwise, generate
     # a callback function in order to hard-code the attribute name.
     context['needs_constructor_setter_callback'] = context['name'] != context['constructor_type']